Not all exchanges are using tokens it's up to you to follow the development of the ICO and to see where it is listed (which exchange to use to trade it). You can use coinmarketcap to save some time but again it's up to you to follow the project that you are taking interest in, and not just grab the free money.
There isn't much minimum to trade but of course, don't waste your time if it worth $0.000001. Regarding how long will it take to convert tokens to ETH it depends on the demand and the volume traded in the exchange.
There is no need for a detailed step by step. Just send your tokens to the exchange then trade it to BTC, ETH or whatever and that's it.
The developer actually gave us a link. The token is in etherdelta. The token is still quite new and is still infamous. I got the token from an airdrop and I am currently joining an different ICO campaign. I asked this to know what to do with the tokens I am about to earn at the end of the ICO. Still learning things about trading and exchanging. If the token is still low in demand, does that mean it will take long before i can convert it?
Most airdrop tokens usually gets dumped once it is listed on exchange and not just airdrop tokens but most of them. If it is a project you believe in, you can hold. Pretty much, you can just convert to ETH quickly when the value is still high and buy some back when it has been fully dumped enough to hold for long and also make some profit at the same time (that is if you believe in the project's success in the long run).
Since you said, the token was listed on etherdelta, I will advise you go through this thread and quickly read through all you need to know about Etherdelta.
https://bitcointalksearch.org/topic/etherdelta-decentralized-token-exchange-2018051 There are some tutorials listed there which can get you going pretty fast. You should also note that it is a decentralized exchange and you will need to make use of your private key in logging in, so I will always be very careful I am entering directly on EtherDelta and not a phishing website cloned as EtherDelta.