Okay, let me comment on VLANs vs. IP.
Firstly, although VLAN, as you likely know, stands for a Virtual LAN (Local Area Network), they really are not Virtual LANs, at least in the older meaning of LANs, which were networks interconnected by (local) "high speed" links (compared to WANs [Wide Area Networks]). The older LANs might be a single L2 domain (as VLANs are today), or it might have been a mixture of L2 and L3 (common in "larger" LANs).
Within the older LANs, you might have, as above, just a single L2 domain, and if so, you didn't need L3 for routing, within the LAN. Or you might have multiple L2 segments, within the older LANs. If you did, just like between L2 segments within a WAN, you can not intercommunicate without L3. It's this later case that VLANs emulate, i.e. totally isolated L2 segments, which cannot intercommunicate without L3, within a LAN or WAN.
Why have multiple L2 segments, within a LAN or WAN? Well, the problem with L2 segments, originally there was a common "wire" that all hosts used to intercommunicate. Think of it much like having a room full of people. Anyone can speak to anyone, but all can hear all conservations. The problem is, it doesn't scale, just like a room of people. Any difference between having 5, 50, 500 or 5,000 people trying to talk between themselves within the same room?
Also on WANs, as their links, compared to LANs, were slow and expensive, do you want all conversations to use the WAN links?
L3 allows us to partition L2 segments, so only traffic that must travel between "rooms" does.
The forgoing make much more sense if, for example, you were using L2 segments using 10Base2, 10Base5 or 10BaseT. L3 routers, were the way to efficiently handle L2 segment intercommunication.
Remember, a key point, hosts within the same L2 segment don't need to use the L3 transit (which, also, BTW, [then] was comparatively slow too).
So, consider a LAN network supporting an accounting workgroup and a marketing workgroup, might be:
(L2 accounting segment) <L3 device> (L2 marketing segment).
Before VLAN switches, you might have an (accounting switch) <router> (marketing switch); notice two physical router connections needed.
But with a VLAN switch, you might have a (VLAN switch [accounting VLAN 5, marketing VLAN 6]) <router>, but how do we connect that VLAN switch to the router?
Or say, you need more ports than one switch provides, so perhaps you have:
(VLAN switch [accounting VLAN 5, marketing VLAN 6]) <?> (VLAN switch [accounting VLAN 5, marketing VLAN 6]) <router>
Besides the VLAN switch connection to the router, how do we also interconnect the two switches?
Well, in both case, since we have two VLANs, we might have two physical connections between the switches and the switch and router, one link, for one each of those two links, assign one to VLAN 5 and the other to VLAN 6, just the same as if we were to configure ports for hosts in those VLANs.
That's not an awful approach for two VLANs, but if we had 10 or 50 VLANs?
The alternative is to use a single trunk link between the switches and the switch and router. On this link, frames are tagged with what VLAN they belong to, so logically, it's just like having separate physical links, one per VLAN.
Notice with these VLAN interconnections, I didn't mention L3, because we're only extending a L2 segment, or VLAN, either using a link per VLAN or a trunk link.
However, if you want traffic to transit between the L2 segments, you need L3, which in the case of the non-VLAN switches, shows VLANs and/or trunks aren't needed.
As you note you have Packet Tracer, try setting up networks, as above. If you get stuck on that, attach your PT file, and I, or others, should be able to help you out.
If the above isn't clear, let me know. BTW, again, this is "basic", but often it doesn't seem that way when first learning it. So, don't be embarrassed to admit still being confused. Most of us all once were, at least I was; often still am too. ; )
