Joining the chorus, but not saying you can't do, be aware that overhauling an amplifier is jumping in to the deep end of the pool, if you have no prior repair experience.
-Get the manual
-Read a lot about repairing amps
-Talk to people.
-Find somebody local who is experienced with amps to help you!!!!!
-Get a thicker hide...people WILL disagree with you on boards.
-DMM with diode function
-capacitor checker (optional)
-Dummy load, appropriately rated (You need it anyway for testing and tuning up)
-Tubes can't be checked on tube testers, they draw too much power. All you can do is a basic short check with DMM, then cross your fingers when turning on the amp.
-Caps. One school of thought is run caps till they blow; that they can be reformed; that slow voltage bring up is best. Other school is replace them if they appear old; turn the power on see if they hold.
-Power supply diodes and resistors should be checked. Replacing with modern diodes is not a bad idea.
-Resistors in the meter circuits should be checked, be precisely accurate or better replaced.
-Check tube bases for overheating, cracked pins and springs.
-Check fuse for correct amperage, clean socket.
-Absolutely confirm that transformer is properly strapped for your voltage!!
-Check wafer/rotary switches for arcing, carbon tracks, corrosion, clean with an alcohol swab. DO NOT use any conductive sprays like DeOxit.
-Remove and measure parasitic suppressor resistor. If drifted more than a few percent, replace with proper value 'non-inductive' resistor, e.g. carbon composite, etc.
-Check overall security, burn or scortched parts, bad solder joints, general cleanliness (use a damp rag).
This is a good start and hits many of the key points.