Start Here

Two short descriptions of how to start sitting practice:

the_pali_line/course/gradualnidana#start

the_pali_line/course/gradualnidana.htm#HIGH_GETTING_HIGH2

Sitting with the intention of creating a satisfied mind (generally a preparation for jhāna, or the burnings):

the_pali_line/course/the great masters satisfaction pastures#PartII

The Practice of the Burnings:
(This might look very lean, but it is in fact pretty much everything the Buddha says about sitting and attaining the Jhānas. Most of the rest of what we get is made up by commentators. I am of the school that what the Buddha taught was well-taught: that in the case of the burnings, less is more):

the_pali_line/course/high get'n high#PartIII

For the experience of other realms, super-normal powers, and the purely mental realms:

the_pali_line/course/the 10th question 1#Part IV

And for the end-game:

the_pali_line/course/the 10th question 2