هذا البرنامج سهل، ولذلك أستعمله كل يوم في المكتب.

Because البرنامج (program) is treated as a masculine singular noun in Modern Standard Arabic, so it takes the masculine singular demonstrative هذا (this).

• هذا = this (masculine singular)
• هذه = this (feminine singular)

So هذا البرنامج means this program.

In Arabic, when a demonstrative like هذا comes before a noun, the noun is usually definite, so it normally takes الـ.

So Arabic says:

• هذا البرنامج = this program

Literally, it looks a bit like this the-program from an English perspective, but that is the normal Arabic structure.

If you said هذا برنامج, it would usually sound less natural in standard usage unless there were a special context.

Because Arabic usually omits the present-tense verb "to be".

So:

• هذا البرنامج سهل literally: this program easy natural English: this program is easy

This is a very common Arabic pattern, called a nominal sentence.

If you wanted was or will be, then Arabic would usually use a verb such as كان or سيكون.

Because سهل here is the predicate of the sentence, not an adjective directly attached to البرنامج.

Compare these:

• هذا البرنامج سهل = This program is easy
• هذا البرنامج السهل = This easy program

In the first sentence, سهل is telling you something about the program, so it does not take الـ.

In the second, السهل is an adjective modifying البرنامج, so it matches it in definiteness.

ولذلك means and therefore, so, or for that reason.

It is made of:

• و = and
• لذلك = therefore / for that reason / because of that

So:

• هذا البرنامج سهل، ولذلك أستعمله... = This program is easy, and therefore I use it...

You may also see just لذلك without و. Adding و makes the connection to the previous clause a little smoother.

أستعمله = I use it

It has two parts:

• أستعمل = I use
• ـه = it / him

So the whole word means I use it.

The أ at the beginning marks first person singular in the present tense: I.

Because Arabic commonly uses attached object pronouns.

Instead of saying a separate word for it, Arabic often adds the object pronoun directly to the verb:

• أستعمل = I use
• أستعمله = I use it

The pronoun ـه refers back to البرنامج.

This is very normal in Arabic and is something learners see all the time:

• أعرفه = I know him/it
• أحبه = I like him/it
• أريده = I want it

Because البرنامج is grammatically masculine singular, and the attached pronoun must match that.

So:

• masculine singular noun → ـه = it / him

In Arabic, non-human things can still be grammatically masculine or feminine. Here, program is treated as masculine, so ـه is the correct pronoun.

Here كل يوم means every day.

• كل = every / each
• يوم = day

So together:

• كل يوم = every day

This is not the same as all day.

For all day, Arabic would usually use something like:

• طوال اليوم = all day long
• اليوم كله = the whole day

So in this sentence, the meaning is definitely every day.

Yes, Arabic word order is fairly flexible.

Here:

• أستعمله كل يوم في المكتب = I use it every day in the office

This is a natural, neutral order.

You could also say:

• أستعمله في المكتب كل يوم

That is also correct. The difference is mostly one of focus or rhythm, not basic meaning.

Putting في المكتب at the end is very normal.

It actually has two different sentence types joined together:

1. هذا البرنامج سهل

   • a nominal sentence
   • no present-tense is

2. أستعمله كل يوم في المكتب

   • a verbal sentence
   • starts with the verb أستعمل

They are linked by ولذلك.

So the sentence moves from:

• a description (This program is easy) to
• a result (therefore I use it every day in the office)

In full formal vocalization, you could write it as:

هٰذا البرنامجُ سهلٌ، ولذلك أستعملُه كلَّ يومٍ في المكتبِ.

The endings are:

• البرنامجُ = nominative, because it is the subject/topic of the nominal sentence
• سهلٌ = nominative, because it is the predicate
• أستعملُه = the verb in the indicative
• كلَّ = accusative, used adverbially in كلَّ يومٍ
• يومٍ = genitive, because it is linked to كل
• المكتبِ = genitive after في

In normal Arabic writing, these short vowel endings are usually not written, so learners often see the simpler form:

هذا البرنامج سهل، ولذلك أستعمله كل يوم في المكتب.