The Dutch coach of Feyenoord is taking charge at the Reds when the season concludes, with only an official announcement remaining.
In an appearance on Dutch television, Brands said: "Don't focus blindly on attracting five Dutch players. He has to look very carefully at what he needs with his style of football. Only settle for top players.
"Slot will be working at one of the biggest clubs in England. You have to realize that. Liverpool has supporters from all over the world, and the pressure is always there. Just like Manchester United, they really are the biggest clubs in England, but it is a fantastic challenge."
Slot then told Voetbal Zone: "That's good advice from people who have worked in the Premier League and have made their mark in football.
"But I don't think you should always judge based on moments from the past. I also read everywhere about the success rate of Dutch coaches in England. There are so many variables. If a player is good, it shouldn't matter what level he comes from.
"But at the moment, there's no talk of anything because nothing has been officially confirmed yet." Slot also admitted he does not know when his appointment will be official, but remains confident the deal will get done.
"These kinds of things always take some time," he explained.
"I have said many times that I am confident that things will turn out well. I can't tell you exactly when it will be released at the moment."