Exodus turns to a construction manual for a few chapters, starting here in Exodus 25 (link). This is not a bad thing to look at as we go through the whole Bible in these posts. One thing we need to understand, overall from these passages, is this truth: God is not to be worshiped as we see best fit. We are to worship as God commands and directs.
Taking a quick divergence into politics, that's actually the essence of freedom of religion: that any person is free to worship God (or gods, or not at all) according to what they believe that God (or gods) command. If it were merely about worshiping how we want then freedom of religion should be subordinate to the will of the people and the winds of the times. Yet if it is about freedom to have no human interference in obeying one's God, then the right of human interference is much more restricted. This is what we had in America, yet we are sliding backwards into the lesser freedom. Those who want to define religious freedom in that manner want to be the ones who tell you how to worship. Do not let them. Even if they are Baptists who agree with me 99% of the time.
Back on track: the first event in this section is a freely given offering by the people of Israel to fund the construction of the Tabernacle and the various components. This was to be taken from those "whose heart moves" and not taken from those who had no interest. In fact, most of the religious offerings of the Old Testament fell under two categories: freewill like this or atonement/sacrificial offerings. The tithe system was more about the operation of the national existence than it was about worship.
One would be right to ask, though, about whose heart could not move them in those times? Here they sit at the foot of the Mountain of God, they're eating manna and passed through the Red Sea. How can they refuse a porpoise skin or two for the construction of a central place of worship? Yet it remains that the offering is for those moved, not for those forced.
Then we see directions for construction. However, those directions do not start with the biggest piece, the Tabernacle itself but rather the most important piece: the Ark of the Covenant. The Ark of the Covenant was the centerpiece in recognizing God's presence in the midst of the people and later contained certain reminders of God's faithfulness and work among the Israelites. Especially important was the "mercy seat" where the blood of annual atonement sacrifice was placed.
Then there is the Table of the Showbread, or the Bread of the Presence. This bread symbolized the presence of God as being real among Israel, and it was eaten by the priests after its allotted time on the Table. Herein lies a key difference between Israelite religion and the religion of many of their neighbors: the Israelites were told upfront that the priests were eating the bread, while many of their neighbors were told that the "gods" were eating the bread, when the priests were just sneaking in to eat it.
Then there is a lampstand to provide light.
Common among all of these items was this: portability. After explaining the cherubim to be placed on the Ark, the sockets for poles for portage are described. The Table has the same feature, and the lampstand is just a portable lamp—you can carry that without a problem.
Why? Because God did not need the bread that was placed before Him, neither in the "bread" of an offering of currency nor the literal bread placed on the table. What He did intend was that His people would learn a crucial fact: this is no regional deity they are covenanting with. This is the God of the whole universe. Sometimes, obeying this God will require not a bolted-down worship center but a mobile people who go in obedience to Him.
This is not what God needs, but what God calls us to do. It is what we, as people created in the image of God, need.
Today's Nerd Note: I almost want the nerd note to be about the location of the Ark of the Covenant, but that is such a wide open discussion that I think it better to let you chase that rabbit on your own. Personally, I like Ethiopia as the resting place of the Ark if it's not in a secret government warehouse from when Indiana Jones found it.
Rather, let's get extra nerdy. It would be easy to try and parallel how the Ark of Noah saved people then and how the Ark of the Covenant was part of salvation for the Israelites, because they're both "arks", right? Except the Hebrew word is different. The word from Noah's Ark is only used again of the basket that Moses is placed in, while the Ark of the Covenant is the same as the word for "chest" as in a storage chest. The word can also mean "coffin" and is the term used for the coffin that Joseph's bones are placed in in Genesis 50:26.
So you cannot properly connect the two, as they are not called the same name. Exactly why they are both translated "Ark" is not a question I can solve. I can move it back to the 3rd century BC, as the Septuagint, the Greek Translation of the Hebrew Scriptures done by Jewish rabbis, used the same Greek word both places. Jerome followed the same practice—it is debated whether or not he knew the Hebrew well enough or was guided by the Greek. Tradition weighs heavily that he knew the Hebrew. Nonetheless, that became the basis of the more well-known text in the Latin Vulgate and English versions followed suit.
Additionally on the Nerd Note: The porpoise skins? Where did they come from? My guess: the Red Sea. Think about the possibility: you're walking between the walls of water and can reach in and snatch one or two of those critters! Alternately, the Israelites would have been able to trade with coastal fishermen at various points and obtain the skins. I like the snatching better, it just sounds more awesome.