What kind of easel do you have? Table-top or upright?
If you think that the canvas is too big even for the easel (i.e. it wobbles and needs you to hold it firmly) - try to secure the vertical/horizontal struts at the back of the canvas to the easel itself (you can use some strong string, or velcro, or cable ties). This way you can sit down easily and work (mind you the canvas will still wobble but you can put your mind at rest, that it will not slide off from the easel).
I usually work sitting down, kneeling, standing, and even standing on a step stool (dimensions of the surface can be a pain) - so usually I have a mobile trolley (one of those 80s TV trolleys), or another chair, or a high stool to put my supplies on (spares me from running all over the place with a loaded brush, and making a greater mess).
There will be times when you will need to have to hold the palette & some brushes in your hands - just be careful that you don't more supplies in your hands than you can handle (am speaking from experience)
I hope these little tips helps.
If you have additional questions, need clarifications or require more specific information, please don't hesitate to holler :)
Bidding you lots of creativity, Ton-Ton