The ico manager will tell you immediately in the market where their coins will be listed first. You can ask that question when ICO takes place. This is especially important if you're an investor
You do not even need the ICO manager to always tell you. If you can stay on the Ann thread, the social media pages of these tokens, or telegram page as well as viewing coinmarketcap once in a while, you will end up knowing when it gets listed. Most ICOs may not even tell you directly where they are going to get listed as they sometimes end up keeping it secret, so at the end, it is either you just chill or keep monitoring the situation of things.