Translation of terms is very easy. I'll give the example with "Total Without Taxes"
1. Go to settings > Application terms > Translated terms
2. Search for the term you're looking for, in this example "Total Without Taxes"
3. You'll now see a record (or multiple) with the original English value and the translation (if there is one).
You can now edit these or add new ones as you wish. In my example I made a translation for English, Flemish and Dutch.
4. When you've translated all the things you want or need you need to synchronize the translations. Do this by clicking on "Synchronize Terms".

Select the language you made a translation for and synchronize. This means if you've translated for Dutch and Flemish you'll need to synchronize the language Dutch AND the language Flemish.
Refresh your page and have a look, it is now translated. (or for example with a new PDF)
Note: If you wish to print a PDF in another language for a customer you will have to place the customer his language on the language you want the PDF to be printed in! This setting is responsible for choosing which language the PDF will have.

While I believe this answers your question I'll also write out the steps about how to translate fields in views.
I'll give the example of the field "Salesperson" when you make a new example.
1. Go to about Odoo and activate the developer mode
2. Navigate to the view where you want to make another translation or term. Then hoover over the fieldlabel where you want to change the name for. For example:

2. Now you know the model (res.partner) and the field (user_id) you can translate it. Go to settings > Application Terms > Translated terms.
3. Search for the term you're looking for, in this example "Salesperson" or alternatively just make a new one.
The first field "Source" is the original text of the label, the second field "Translation value" is the value that you want it to show in your language, field three (translated field) is the name of the model with the name of the field. As you can see in the hoover over the label you have the model res.partner and the field user_id so this would become res.partner,user_id. The fourth field is the language you want to translate for and the fifth field is the kind of text you want to translate. In this example this is a type "field".
So you'll get something like this:

4. Synchronize the translation for the languages you've translated and refresh the page. You're done now.
5. The result: