How to wind a good warp and get it on the loom without tension problems is something every new weaver needs to learn.
I use weights, as they are always around whereas I don't always have a friend handy to hold the warp for me. In some respects weights can work better, as a person has two hands and can hold up to two bundles of warp separately, but you can tie weights on every few inches of warp threads.
Here are my weights, attached to the chained warp. They are tied to hang slightly above floor level at the start.
I have tied them on with a medium weight linen warp yarn tied in a simple slip knot (or half hitch, depending how you look at it).