You don’t need much space at all….the end of a table, or a corner of a room are fine.

It’s best to work upright if you can, with a board on an easel, a table easel, or just rested on a pile of books. This means that any dust will drop down, and won’t pollute your work, and also that you can stand back regularly to review your work and see ‘the bigger picture’.

Table easel.
Studio set up with easel.