From Vancouver Yarn blog
Warp: the yarn that is wrapped around the loom under tension.
Weft: the yarn that is passed back and forth through the warp.
When weaving, you draw your between two sets or warp threads.
Shed: the open space found between the warps at the back and the ones at the front.
To lock in one thread of weft that has been passed through, you must change the shed.
One way to do this is to pick up the back warps so they are acting as front warps.
This loom is set up in a way that has one shed that is always open.
This means that to change the shed, you will only have to pick up threads going one way.
The other shed is open by default while your loom is in a resting state.
If you have warped up as per the previous video and your open shed is hard to get into, try entering the shed from higher up on the loom, sliding your hand down, and you may need to tighten your tension using the nuts on your loom, too.
Now let’s slow down and do this step-by-step.
To begin weaving, send the weft bundle through the open shed in sections.
Beat down your weft with a fork.
Pick up the back warps in sections; a back warp will come up between two front ones.
Be sure to note if an edge warp should be picked up. Warps alternate, one up, one down.
Continue across, creating bubbles.
Beat with a fork (again), and go back through your open shed (as before).
In either shed, only pass through an amount that is easy for one hand to work with.
Bubbling the weft allows it to distribute evenly and fully cover the warp.
In tapestry weaving, we generally try to completely cover our warp threads with weft.
At the beginning, you can fiddle with it. Pack it down more, squishing the top and bottom.
The more you weave, the stronger the base and easier it will be to cover the warps.
Now, continue weaving, using those steps, and make a 1-2″ bottom section from which to work.
When you run out of yarn, avoid leaving ends on the edge; instead, end them inside.
Continue in the same shed with new weft adjacent to the area you just wove (6:08).
You can decrease by turning around at any warp thread while weaving.