Jo tydeligere nettselskapet forklarte, desto enklere ble strømavtalen.

It is a correlative comparative pattern. It means:

• the more ..., the more ...
• the more ..., the less ...
• the less ..., the more ..., etc.

So this sentence follows the pattern:

• Jo tydeligere ...
• desto enklere ...

= The more clearly ..., the easier ...

A very common example is:

• Jo mer du øver, desto bedre blir du.
• The more you practise, the better you get.

No. In this sentence, jo does not mean yes.

Norwegian jo can have several uses, and this is one of them. Here it is just the first part of the comparison pattern jo ..., desto ....

So in this sentence:

• jo = the more / the less part of the structure
• not yes
• not really indeed either

Because they are comparatives.

• tydelig = clear

• tydeligere = clearer / more clearly

• enkel = easy / simple
• enklere = easier / simpler

In this kind of sentence, Norwegian uses comparative forms after jo and desto.

So:

• Jo tydeligere ... = The more clearly ...
• desto enklere ... = the easier ...

Because it is connected to the verb forklarte.

• nettselskapet forklarte tydeligere = the company explained more clearly

English usually changes clear into the adverb clearly, but Norwegian often uses the same basic form for adjective/adverb meanings in this kind of context.

So even though tydeligere looks like clearer, in this sentence it functions like more clearly.

Because the first jo-part behaves like a subordinate-clause-style structure.

In ordinary main clauses, Norwegian often has verb-second word order. But in a jo ... desto ... sentence, the first clause usually keeps the order:

• subject + verb

So:

• Jo tydeligere nettselskapet forklarte ...

not:

• Jo tydeligere forklarte nettselskapet ...

This is normal for this construction.

Because the second clause is a main clause with verb-second word order.

The element desto enklere comes first, so the finite verb must come next:

• Desto enklere ble strømavtalen.

Structure:

• first position: desto enklere
• second position: ble
• then the subject: strømavtalen

This is standard Norwegian word order after fronting something other than the subject.

The object is understood from context and does not have to be stated.

In English, we might expect something like:

• the company explained the agreement more clearly
• the company explained the terms more clearly
• the company explained things more clearly

Norwegian can leave that unsaid when it is obvious from the situation. The sentence focuses on the result: the contract became easier to deal with or understand.

Because they are in the definite form:

• nettselskap = a grid/power network company

• nettselskapet = the grid/power network company

• strømavtale = an electricity contract
• strømavtalen = the electricity contract

Norwegian usually adds the definite ending to the noun itself:

• -et for many neuter nouns
• -en for many masculine nouns

So here the sentence refers to specific things, not just any company or any contract.

You can also say jo ..., jo ....

For example:

• Jo tydeligere nettselskapet forklarte, jo enklere ble strømavtalen.

That is also natural Norwegian.

A simple rule of thumb:

• jo ..., desto ... = very common, often feels a bit more formal or written
• jo ..., jo ... = also common, especially in everyday speech

Both express the same basic idea.

Yes. Ble is the past tense of bli, which usually means become.

So literally, the second part is something like:

• the electricity contract became easier

In English, we might translate that more naturally in different ways depending on context:

• the contract became easier
• the contract was easier to understand
• the contract seemed simpler

But grammatically, Norwegian is using bli to show a change in how the contract was experienced or understood.