Please help and clearly explain step by step

Create the following queries using the correct tables:

a$.$ List the names of places from which the company sells. Show all columns in the table. Name this query Q$1-$SELLING$-$LOCATIONS.

b$.$ What is the total sales by location for May $2008,$ sorted in descending order? Name this query Q$2-$SALES$-$MAY$2008.($Hint: $$Where$$ clause may be useful$)$

c$.$ The company has been informed that the tax has been increased to $17\mathrm{.}5\%.$ Calculate how much additional tax $($i$.$e$.,$ the difference$)$ the store would have collected by year. Name this query Q$3$ ADDED$-$TAX.