CTRL-^ - switch to the alternate buffer. It’s indicated in your buffer list with the symbol #.
:buffer <ID_or_name>- Move to the buffer using its ID or its name.
:bnext or :bn - Move to the next buffer.
:bprevious or :bp - Move to the previous buffer.
:bfirst or :bf - move to the first buffer.
:blast or :bl - move to the last buffer.