You need the cncnetclient to run it on cncnet which is on this website at https://cncnet.org/red-alert
You can download red alert free, its ra2 and ra2yr that you need to pay for.
You still need to down load the cncnclient for ra2 and yr but the cncnetclient will search for the game on your hard drive first to verify you have bought the game as it isnt freeware.