Teorik eğitim ile uygulamalı eğitim birlikte planlandı.

Here, ile links the two noun phrases:

• teorik eğitim ile uygulamalı eğitim

In this sentence, ile is functioning like and / together with.
So it connects theoretical training and practical training.

A very common alternative would be ve:

• Teorik eğitim ve uygulamalı eğitim birlikte planlandı.

Using ile can sound a little more formal or slightly more like together with than plain ve.

Because they do slightly different jobs.

• ile connects the two noun phrases
• birlikte describes how the planning happened: together, jointly, as one combined plan

So birlikte adds emphasis that the two kinds of training were not planned separately.

Without birlikte, the sentence is still grammatical:

• Teorik eğitim ile uygulamalı eğitim planlandı.

But with birlikte, the idea of joint planning is clearer.

Planlandı comes from the verb planlamak = to plan.

It can be broken down like this:

• planla- = verb stem
• -n- = passive marker
• -dı = past tense

So planlandı literally means something like:

• it was planned
• or, in context, were planned

The passive is important here because the sentence does not say who did the planning. It focuses only on the result.

This is very normal in Turkish.

Even when the subject is plural or compound, Turkish very often uses a singular verb, especially in formal or neutral statements. With passive verbs, this is especially common.

So:

• Teorik eğitim ile uygulamalı eğitim birlikte planlandı.

is completely natural.

English usually says were planned, but Turkish does not need to match that plural in the same way.

Turkish usually puts the verb at the end of the sentence.

So the basic order here is:

• Teorik eğitim ile uygulamalı eğitim = subject/topic
• birlikte = adverb
• planlandı = verb

That makes the sentence very standard and natural in Turkish.

A rough pattern is:

• [Subject] + [Adverb] + [Verb]

Since Turkish is flexible, other orders are possible for emphasis, but this one is the neutral word order.

Uygulamalı means practical, applied, or with practice/application.

It is formed from:

• uygulama = application, practice
• -lı / -li / -lu / -lü = a suffix meaning with, having, characterized by

So:

• uygulama + lı → uygulamalı

A useful warning: even though -malı / -meli is also a well-known verb ending meaning must/should, that is not what is happening here.

So uygulamalı eğitim does not mean training that must be applied.
It means practical/applied training.

Yes, Turkish could say it only once:

• Teorik ve uygulamalı eğitim birlikte planlandı.

That is also correct.

In your sentence, eğitim is repeated because each type is presented as its own full phrase:

• teorik eğitim
• uygulamalı eğitim

Repeating the noun can make the contrast between the two types a little clearer or more balanced.

So both are possible:

• Teorik ve uygulamalı eğitim...
• Teorik eğitim ile uygulamalı eğitim...

The version with repetition sounds slightly more explicit.

Turkish does not use articles the same way English does.

So Turkish often just says:

• teorik eğitim
• uygulamalı eğitim

without anything corresponding directly to the.

Whether English translates this as the theoretical training, theoretical training, or a theoretical training program depends on context, not on an article in Turkish.

Because eğitim here is being used as a general category or type, not as countable separate items.

Turkish often leaves nouns singular when talking about kinds of things:

• teorik eğitim
• uygulamalı eğitim

Using eğitimler would sound different and would suggest multiple separate training programs/sessions in a more countable sense.

So the singular form is the natural choice here.

Yes. If you want to say who did the planning, Turkish would usually use an active sentence.

For example:

• Teorik eğitim ile uygulamalı eğitimi birlikte planladılar.
  = They planned the theoretical and practical training together.

In your original sentence, the passive:

• planlandı

is used because the doer is unknown, unimportant, or simply not mentioned.

That is very common in formal, administrative, and academic Turkish.