Like bobss396 says. It will probably go something like ‘install with assembly lube, soak the lifters (if hydraulic) in oil and pump them with a pushrod to get air out, then install, pre-lube the engine with a shaft to drive the oil pump with a 1/2 inch drill or better (it’s nice to remove the valve covers to see when oil gets up top... it takes a lot longer than one would think... you could do this with the starter if the coil wire is removed, but it takes a long time), reinstall valve covers, set timing close, fire it up, set timing closer real quick, run at 2000-2500 rpm or so for 20-30 min. Check oil pressure and water temp as you go. Use a good break in oil, especially if you’re breaking in more than the cam’. have a beer.
One really big thing right off the bat....got to have a high ZDDP content break-in oil. Do the break-in with current conventional off-the-shelf motor oils and you'll soon be tearing it apart to replace a flat cam. All current cars are roller cam, ZDDP harms catalytic converters and so the EPA has mandated it's removal from current motor oils Diesel motor oil like Rotella don't cut it either, before some yahoo comes in and recommends it. Do it right or do it again. I'd recommend a moly paste on cam lobes and lifter bottoms, no runny cam lubes especially not that red crap Comp Cams sends out. Crane Moly paste or Isky Rev-lube or equivalent. Pre-oil the system with a pump driver tool and drill motor, pre-fill carb bowls with gas through the bowl vents so you don't have to crank the starter to fill them, try to get the base ignition timing set somewhere close to 20-35° Before TDC so the engine immediately fires up and runs advanced enough to not make excess heat, crank idle speed screw up 1-1/ to-2 turns before fire-up to ensure an immediate 2000+ rpm engine speed. Any starter cranking without immediate fire-up is just wiping cam lube off the lobes and lifter bottoms....that's why you want to avoid cranking the starter to oil the lifters and pushrods or fill the carb bowls. Engine needs to run 20 minute+ at 2000-3000 rpm to ensure plenty of oil splash getting to cam during break-in. ABSOLUTELY ZERO time spent at idle on fire-up. Have a shop fan ready to help blow on radiator and engine if needed, have a garden sprayer full of water also on stand-by, to fog the radiator fins if heat becomes a problem....you do not want to have to shut the engine off early. I can proudly say in at least 25 flat tappet cam break-ins over the years, I've never lost a cam.
Many cam makers now say specifically NOT to soak the lifters in oil. I like to use something good and thick like Permatex Ultra Slick on the lifters and pushrods, also the rocker arm wear-surfaces. Always use the cam lube that comes with the cam on the lobes. If the cam maker suggests a ZDDP-rich oil additive, use it. I use any one I find locally, doesn't have to be the same brand as the cam. I like to pre-oil the hell out of everything and have a gutted distributor that works well. I use a big 1/2" electric drill motor. The last one I did, I plumbed an oil pressure gauge into the back on the intake. Just to make sure you have some pressure, anything over 20 psi is good. I did the 1st one, rotate the engine a 1/4 turn and repeat until all rockers have oil up through them. Very important like Eric suggests, make sure the engine can run for the cam break in. Meaning the coolant system is hooked up and you have enough gas in the tank. In a best world, I like to have the exhaust hooked up so I can hear anything bad going on.