This is a tutorial which will enable you to do the flashcard exercise click here to see it
Try to learn and understand the contents of the tutorial and then go and see how well you do with the flashcards.
Here we are practising with the verb "DAR" (to give) which is one of the most common verbs which can take two object pronouns.
Once you have mastered this, you will also be able to use other verbs that have two objects such as "enviar" (to send), "vender" (to sell), etc.

If you are a typical English speaker, you may well not be familiar with grammatical concepts such as subject and objects.
If you look it up in WIKIPEDIA, you will probably get really confused.
We only need to understand this in the most simplistic way.

The subject is the person or thing that does the action.
The object in a sentence is the entity that is acted upon by the subject
So in the sentence "I ate a banana." - I is the subject and banana is the object.
In Spanish, the subject of the verb is contained within the verb. e.g. trabajo = I work, trabajas = you work, etc.

By the way:
Transitive verbs require an object. Intransitive verbs do not an object.

In this tutorial and flashcard exercise, we are are going to use the verb "DAR" which has both a direct and an indirect object.
In the case of "give" the direct object is the thing given and the indirect object is the person or thing that the object is given to.
As you can see in the table below in English there are 2 possible word orders: DO ID (= DIRECT OBJECT INDIRECT OBJECT) and ID to DO Have a look.
In Spanish the pronouns come before the verb and the order is ID DO VERB

Whenever both pronouns begin with the letter "L" we change the first pronoun to "se."

le la = se la
le los = se los
le las = se las
les lo = se lo
les la = se la
les los = se los
les las = se las