I’ll try to answer, the mods can surely improve on that.
I hope this helps (= HTH):
@Freedom: Under each post of someone else I have 4 things on the right hand side:
The one on the left is the outline of a heart. When you click that, it goes red. That means you have ‘liked’ the post. (That doesn’t necessarily mean you are happy about things in the post, it can also mean ‘support’ for things that are sad or difficult, ‘thanks’ for help, or ‘useful’ for good ideas, but also enjoying it. So you are actually right when you say that you are liking someone, rather than the post, because you are liking someone because of the post.)
To see the latest likes others have given you, you click on your avatar/picture at the right of the top of the page.
The second most important thing in the line under the post is on the right hand side “reply”. If you click on this, your reply is an answer to that post and person, which helps everyone see that more clearly. If you just go on reply under the thread, then you are replying in general, not to that person/post, which can get confusing if a lot is going on.
Another way you can make sure someone knows you are addressing them is by putting the @ in front of their name, which I am doing in this post by addressing @Freedom and @gramybear.
The third most important thing is under your own posts: There is no heart there - we all are hoping everyone here is liking themselves all the time, and striving for that ;-). But second from left there is a pencil. That lets you edit the post for about a month(?) after you’ve written it, which I do continually… 
@gramybear: To see all the latest posts, wherever they may be hiding, we can click on the 3 horizontal lines (hamburger menu) in the top right corner, to the left of your avatar/pic. Then click on ‘latest’. Learnt that from @AussieMom. A keyboard-shortcut for this is pressing g and then l (for l-atest). Learnt that from TJ at @ModSupport. It doesn’t work in certain situations, like now when I’m writing a post myself … gl. Learnt that by repeatedly trying it out.
