"Also the Harrison, the Musucal Traditions Club and the Cellar Upstairs are all only a short tube ride away. "

From Russell Square it would be easier to walk to all three. (Cellar is about 15 minutes walk straight down Guildford Street)

Use the TfL website for directions at https://tfl.gov.uk. You can set the maximum time that you are prepared to walk and it will give you the fastest route on foot or by public transport with maps.

Don't forget that you cannot use cash on the buses and you pay a premium for buying paper tickets on the Tube. Use a contactless debit / credit card or get an Oyster card on arrival. (see TfL website for details).