عندما يبدأ التسجيل في الدورة، يقرأ المتدرب استمارة التسجيل.

عندما means when. It introduces a time clause, so the first part of the sentence tells you when the main action happens:

• عندما يبدأ التسجيل في الدورة = When registration for the course begins
• يقرأ المتدرب استمارة التسجيل = the trainee reads the registration form

So عندما works a lot like when in English.

Both are possible in Arabic, but verb + subject order is very common in MSA.

Here:

• يبدأ = begins
• التسجيل = registration

So يبدأ التسجيل literally has the order begins registration.

This is a normal Arabic sentence pattern. If you said التسجيل يبدأ, that would also be understandable, but it would sound more like you are emphasizing registration.

Because the subject is التسجيل, and التسجيل is a masculine singular noun.

So the verb agrees with it:

• يبدأ التسجيل = registration begins

If the subject were feminine singular, you would usually use a feminine verb form instead.

Also, because the verb comes before the subject here, Arabic uses the singular verb form, which is the normal pattern in verb-first sentences.

التسجيل is a verbal noun, often translated as registration or enrollment.

It comes from a verb related to registering. In this sentence, it functions as a noun, not as a verb:

• يبدأ التسجيل = registration begins

So this is not saying someone registers. It is talking about the process or period of registration itself.

في means in or for, depending on context.

• الدورة = the course
• في الدورة literally = in the course

But in natural English, this phrase is often understood as for the course or in the course/program depending on context.

So:

• التسجيل في الدورة = registration for the course

Arabic often uses في in places where English might prefer for.

الدورة means the course. The الـ is the definite article, like the in English.

So:

• دورة = a course
• الدورة = the course

In this sentence, it sounds like a specific course is meant, not just any course.

المتدرب means the trainee.

It comes from a root related to training. It is an active participle, a very common Arabic pattern used for people who do an action or are characterized by it.

So:

• متدرب = trainee
• المتدرب = the trainee

Depending on context, it could also be understood as the learner or the person in training, but trainee is the most direct meaning.

Arabic often uses the present tense for general statements, routines, or actions connected to another event in a time clause.

So this sentence is describing what happens at that time:

• When registration begins, the trainee reads the registration form.

It is not necessarily talking about something happening right now. It can describe a normal procedure or a repeated situation.

استمارة التسجيل means the registration form.

This is an iḍāfa construction, often called a possessive or noun-linking structure:

• استمارة = form
• التسجيل = registration
• استمارة التسجيل = registration form

In an iḍāfa, the first noun usually does not take الـ, even when the whole phrase is definite.

So:

• استمارة تسجيل = a registration form
• استمارة التسجيل = the registration form

The second noun, التسجيل, makes the whole phrase definite here.

Because it plays two different roles:

1. التسجيل in يبدأ التسجيل = registration as the subject of begins
2. التسجيل in استمارة التسجيل = registration as part of the phrase registration form

So even though it is the same word, its function is different in each place.

In this part:

• يقرأ = reads
• المتدرب = the subject = the trainee
• استمارة التسجيل = the object = the registration form

So the structure is:

• reads
  • the trainee
    • the registration form

This is another common Arabic pattern: verb + subject + object.

Yes. In fully vocalized MSA, the words would have case endings, although they are usually omitted in normal writing.

Grammatically, they would be:

• يبدأُ التسجيلُ — التسجيلُ is nominative because it is the subject
• في الدورةِ — الدورةِ is genitive because it comes after في
• يقرأُ المتدربُ استمارةَ التسجيلِ
  
  • المتدربُ is nominative as the subject
  • استمارةَ is accusative as the direct object
  • التسجيلِ is genitive as the second part of the iḍāfa

Learners often do not see these endings in everyday printed Arabic, but they are still part of the grammar.

Yes. Even if the meaning has already been given, it is useful to know that the Arabic present tense here can describe a standard procedure.

So the sentence can sound like:

• When registration for the course begins, the trainee reads the registration form.

This may mean:

• that this happens regularly,
• that this is the usual sequence,
• or that this is what one is expected to do.

So the sentence is not limited to one single moment in time.