A Ana e a Maria apoiam-se uma à outra quando o trabalho corre mal.

In European Portuguese, it is very common to use the definite article before a person's name:

• a Ana
• o João
• a Maria

So A Ana e a Maria sounds natural in Portugal. English normally does not do this, which is why it feels strange to English speakers at first.

Because the subject is plural: A Ana e a Maria = two people.

So the verb apoiar has to be in the 3rd person plural:

• ela apoia = she supports
• elas apoiam = they support

Here, Ana + Maria gives you apoiam.

Here se shows a reciprocal idea: the action goes from each person to the other.

So in this sentence, apoiam-se means something like:

• they support each other
• they support one another

Be careful: se can also be reflexive in other sentences, meaning someone does something to themselves. Here it is reciprocal, not reflexive.

Because in standard European Portuguese, object pronouns like me, te, se, lhe, nos are often attached after the verb in affirmative main clauses. This is called enclisis.

So:

• apoiam-se is the normal European Portuguese pattern here

The hyphen shows that the pronoun is attached to the verb.

Yes, se already suggests a reciprocal meaning here, but uma à outra makes it clearer and more explicit.

So:

• A Ana e a Maria apoiam-se = Ana and Maria support each other
• A Ana e a Maria apoiam-se uma à outra = same idea, but more explicit/emphatic

This helps avoid any possible ambiguity and stresses the mutual relationship.

Because the sentence is about two female people.

The reciprocal expression changes according to gender and number:

• um ao outro = one another, for two masculine people or a mixed pair
• uma à outra = one another, for two feminine people
• uns aos outros = one another, for a masculine/mixed plural group
• umas às outras = one another, for a feminine plural group

Since both Ana and Maria are feminine singular individuals, uma à outra is the correct form.

À is the contraction of:

• a
  • a

In uma à outra, the first a is a preposition, and the second a is the feminine singular article before outra.

So:

• a + a = à

The grave accent in à marks this contraction. It is not just an accent for pronunciation.

Because um ao outro / uma à outra is a set reciprocal expression meaning one another.

The a here belongs to that expression, not really to the verb apoiar itself.

So even with verbs that do not normally take a, you can still get:

• amam-se um ao outro
• ajudam-se uns aos outros
• apoiam-se uma à outra

In other words, think of uma à outra as a fixed pattern meaning one another, not as a direct result of the verb's normal preposition.

In European Portuguese, apoiam-se is the normal form in this kind of affirmative main clause.

Se apoiam would sound:

• more Brazilian in many contexts, or
• natural only when a word triggers the pronoun to come before the verb

For example, in European Portuguese you do get pronouns before the verb after certain triggers:

• não se apoiam
• quando se apoiam
• que se apoiam

But in your sentence, the main clause is a normal affirmative statement, so apoiam-se is the expected European Portuguese form.

No. The verb apoiar can appear in different ways.

For example:

• apoiar alguém = to support someone
• apoiar-se em alguma coisa = to lean on something
• apoiar-se with a plural subject can also express a reciprocal idea = to support each other

So in this sentence, apoiam-se does not mean they are physically leaning on each other. It means they support each other.

This is a very common idiomatic use of correr in Portuguese.

Although correr often means to run, it can also mean:

• to go
• to proceed
• to turn out

So:

• corre bem = goes well
• corre mal = goes badly / goes wrong

In quando o trabalho corre mal, the idea is that the work situation is not going well.

It depends on context. O trabalho can mean:

• work in general
• the job
• the task/project they are dealing with

So the sentence could refer to:

• their work life
• a piece of work they are doing
• a professional situation

Portuguese often uses o trabalho in a broad way where English might choose between work, the job, or things at work depending on context.

Yes. You could also say:

Quando o trabalho corre mal, a Ana e a Maria apoiam-se uma à outra.

That is completely natural. The meaning stays the same. The difference is mainly one of focus and rhythm:

• ending with quando o trabalho corre mal keeps the time/situation as extra information at the end
• starting with it gives that situation more prominence right away