The first work is to add to your installation, the "apps", ( the processes) that you will need; to do this you use the configuration menu on the right side of the top line of the screen. 

It is highly recommended to add new apps very progressively - one after the other - once you are familiar with the tool.

You will start with the app that has the highest priority for you.

Odoo has a great modularity; the next app you will install will instantly collaborate with the previous ones.

Once one app is installed you need to setup some parameters to customize to your domain.

For instance you need to carefully set up your company's details : address, bank account, logo, tax number, currency etc; you will find these parameters on the left side menu bar (configure---> company)

The same after the first operational app you have installed.

The next steps consists in populating your database.

create your first product; and create one supplier and one customer

Once done you will be able to buy or purchase the product.

That is all for today

Good luck!

little help from here, we call saas 1.0, now it upgrades to saas 2.0

https://www.youtube.com/channel/UCwR0FuvqqvA2HNY9BF90Syg

Pak Tony, you can read this: https://readthedocs.org/projects/odoo-saas-tools/