I need help adjusting my cam chain on my T80 as the Haynes manuel doesn't explain it well and need explaining in laymen's terms,

Thanks

Seemed to remember there is a domed nut on the LH side of the cylinder head you undo and take off with a locknut underneath which you just loosen then loosen the cross head screw then retighten screw and locknut. Can,t remember if this is done with engine running or with the engine at TDC on the compression stroke. Does the Haynes mention this ?

Tony