Assist with setting up shopify backend

The majority of my website and shopify has been set up however I need assistance customising shipping & delivery options, different zones postage prices, mix and match products purchases , product discounts if purchasing a certain amount, shipping calculator, app downloads, adding products, wholesalers account (able to see a different price compared to normal customers) among a few minor site adjustments. The goal is to have the website/shopify up and running, fully functional. I need this job to be finalised before Thursday 31st.