ARC LS5MKII and VT100 schematich help to replace tubes

Hello people,
I’m searching help from anybody with vacuumm tube audio equipments knowledge to help me.
I’ve a Audio Research LS5 pre and VT 100 amp recently re-tubed sounding pretty well with recomended ARC tubes.
When I purchased the new tubes I purchase a single pair of "reflector 6H23n-EB" and another single pair of "Genalex 88CC/6922” Gold Lion to taste new sound.
I wrote to ARC to know wich tubes was most recomended replace for test the flavor of these new tubes and I sent them the schematic and pictures marked with numbers to they could tell me what function have and do each tube... input, bias current, output... etc
and friendly they told me only what consider better to replace for this.

But I would like to ask for somebody with schematics knowledge if could tell me what do each tube from schematics, to know what process each tube have.
I send the schematic and pictures marked.
From ARC support told me for LS5 and with a sigle pair replace V1 from each channel. and it would better if I can replace V1 and V2 from each channel.For VT100 same: to replace V1 (first L chanel) and V2 (first R chanle)
But don’t told me what tube workfuntion is each tube have.

From the schematic and pictures
¿Anybody knows what tube do?¿Could anybody help me?it was very helpfull to me understand it

LS5MKII (6922 tubes)V1: ?
V2: ?
V3: ?
V4: ?
V5: ?

VT100 (6922 tubes)
V1: ?
V3: ?
V5: ?
V7: ?

LS5 picture
LS5 Schematic
VT100 tubes picture
VT100 schematic
VT100 manual tubes place