wound care

I am a beginner tarantula hobbyist and had seen online a plastic box to hold your tarantula in when you repiar wounds that gives you safe access to top and bottom and legs of tarantula. Is this normally how you repair wounds or injuries or do you hold them in hand? I know about the new skin and such but need to know how to secure the tarantula while applying the new skin.....

Any help would be greatly appreciated......

I don't know about anybody else but my Ts, I have over 40, Have never needed this kind of treatment. Keep them so they don't have a high risk of falling and hurting themselves. If they hurt a leg just leave it and it will come off and the T will grow another with the following molts. If the leg doesn't come off but is still leaking hemolymph (T blood) grab it with a pair of tweezers and don't let go, the spider will shed the leg, and be able to shut off the flow at the leg joint.