Questions about planner methods

Hi List(s);

I'm wanting to find more details per the following methods, can someone
explain to me exactly what each of these methods is, how its implemented in
postgres or point me to some docs or README's that explain these methods?

Some of 'em are obviously no-brainers but I'm writing a postgres book and want
to make sure I convey the concepts properly and technically correct.

- Bitmap Scans
- Hash Aggregation
- Hash Joins
- Index Scans
- Merge Joins
- Nested Loop Joins
- TID Scans

Thanks in advance for your help...