weight painting problem/s

hi guys ime new to blender and cg in general i have built a skeleton onto a very basic model
to test armature rigging following this tutorial

but when i get to weight painting i come unstuck as no matter how many times i try i cant paint the whole of an area i need to it paints something close to it so i turn on a button that says paint only vertices selected in vertex group and it only paints parts no matter the size of the brush i use plus when i do get it done as best i can the tuteial says rotate the arm and notice the mesh moves but it just doesnt for me please guys where am i going wrong your welcome to the blender file thx guys i knoow ime dumb :slight_smile:

When in weight paint mode, press f, which will allow you to select faces with the right mouse button. Then, when you paint, it will only weight the selected face/s. Are you rotating the arm in pose mode?

i tried in pose mode and just about every mode there is lol still the same 1 thing to add too
after weight painting it doesnt let me paint another set of vertices untill i click on vertex groups then group i had it working just the i closed it and started again to see if i could do it again now i have the same problem

now ime confused lol i just parented the armature to the mesh now weight painting works fine yet the tutorial didnt say anything about parenting them will this way cause me problems or am i ok to carry on ???

You’re fine to carry on. When you parent the mesh to the armature, a modifier appears in the modifier panel. Press the make real button to access the other modifier functions for the armature.