In this chapter, the LORD establishes the ritual of the grain offering.
This chapter is substantially similar to the last one in its general attitude, although the specific details vary a bit.
Probably the most significant variation is that, unlike the burnt offering, only a handful of the grain offering is burnt on the altar: the rest is given to the priest as his sustenance. In the case of the burnt offering, it is likely that the officiating priest would have been given the skin of the animal, but in the case of the grain offering, the priest is given nearly everything. This is similar to what we saw in the sacrifices for consecrating the priests back in Ex 29:26-28, where the "wave offering" was given to the priest as food. The consecration only happens once: the sacrifices here would have been given by many Israelites throughout the year, and so it was by receiving portions of the offerings that the priests made their livelihood.
We can already see that some offerings are more "profitable" than others, but since the offerings are often made in combination, this isn't really an important distinction. Neverthless, I think it's interesting to observe the duality of the offering, that part of it is offered to the LORD ("a soothing aroma") and part of it is given to the priest. In a certain sense, the entire offering is supposedly given to the LORD, in the sense that the people are "present[ing] a grain offering as an offering to the LORD" (v. 1). Obviously the people are not supposed to make offerings to the priests in any way, because that would be ascribing honor to the priests that is intended for the LORD. However, the LORD has created a provision that part of the offering goes to the priests, but it's almost like this is downplayed in the text because that's not really the intention of the sacrifice. And yet the priests are allowed to take from the offering, which positions them in the offering that is ostensibly between the people and God. This is another aspect in which the priest intermediates between God and the people.
Many ways to prepare the grain offering are allowed. At first, this seems like a parallel to the last chapter where three different types of sacrifices were allowed (calf, goat/sheep, bird). However, the big difference is that the various burnt offerings had different monetary values, while the various grain offerings are largely equivalent in cost. In fact, we are not even told the quantity of grain that must be offered, which makes it impossible to assess the actual cost of performing a grain offering. My suspicion is that there was some social standard or extra-biblical regulation governing the quantity of a grain offering, but I have no confirmation for this.
Still, one can hypothesize that the poor could offer less grain than the rich, because these regulations do not restrict the poor from doing so.
The people are commanded to use no leaven in their offering. Obviously this is reminiscent of the Passover regulations. Remember that with the Passover, the bread was unleavened because of the haste of the people in their departure from Egypt. Now there is no such rationale. Either the ritual is intended to remind us of the Passover (certainly possible) or there is an alternative reason for not leavening the bread. My understanding is that in later times, leaven was considered a metaphor for sin, and it's possible that this metaphor was also intended back when Leviticus is written. Since this chapter does not tell us, it is left to the reader to discern what meaning one will.
Lastly, verse 13 uses the phrase "salt of the covenant". This is yet another unexplained expression, and this is the first place it is used. It is repeated in similar terms later on in the OT as well, in the book of Numbers and 2nd Chronicles. In my opinion, salt is a metaphor for preservation and endurance. Salt was historically used as a preservative, so I think it's sensible to think that "salt of the covenant" is meant to emphasize the preservation or endurance of the covenant itself. Alternatively, we can think of it as the preserving influence of the covenant upon the people. Either way, this phrase is only used a handful of times so it is not a major theme in the OT.