I forgot to include the following sentences. Can you please have a look at them, too?

1)Their voyage starts from (better: begins at Tabard Inn) Tabard Inn in London, that is connected to (with?) pleasure and ends in Canterbury, a symbol of the celestial city of Jerusalem.
2) Can you also say: "The pilgrims start from (set off at..) Tabard Inn and travel ( are directed) towards Canterbury".
3) The whole project would have included 120 tales if Chaucer had finished it.
4)In the General Prologues and (as well as)) in the prologues before the tales the pilgrims are presented with reference to their clothes, appearance and professions.
5)Don't switch from the past to the present when describing the themes dealt with in the tales.
6) As for the themes dealt with in the tales, the main are those of marriage, love, corruption, and chivalry.
7) The themes dealt with in the tales (also: presented/described in the tales?) are those of love and marriage./The tales deal with various themes, among which love and marriage.
8) Canterbury Cathedral is a symbol of the celestial city of Jerusalem. This means (?) that we are all pilgrims on a travel (better: on the way) towards the celestial city.

1)Their voyage begins at Tabard Inn in London, that is connected to (with?) pleasure and ends in Canterbury, a symbol of the celestial city of Jerusalem.

This sentence is strange. Tell me what "that" is referring to, and I'll know better how to rephrase it.

2) The pilgrims start from Tabard Inn and travel towards Canterbury.
Yes, that's fine.

3) OK

4) In the General Prologues, as well as in the prologue before each tale, the pilgrims are characterized by their clothes, appearance, and professions.

5)Don't switch from the past to the present when describing the themes dealt with in the tales.

6) The main themes dealt with in the tales are those of marriage, love, corruption, and chivalry.

7) The themes presented in the tales are those of love and marriage.

8) Canterbury Cathedral is a symbol of the celestial city of Jerusalem. This implies that we are all pilgrims on a journey towards the celestial city.

Read and compare carefully...

Sure, here are the revised sentences with suggested improvements:

1) Their voyage begins at Tabard Inn in London, which is associated with pleasure, and ends in Canterbury, symbolizing the celestial city of Jerusalem.
2) Another way to express this is: "The pilgrims set off from Tabard Inn and journey towards Canterbury."
3) If Chaucer had completed the entire project, it would have included 120 tales.
4) In both the General Prologues and the prologues preceding the tales, the pilgrims are described based on their clothing, appearance, and professions.
5) It is important to maintain consistency in verb tense when describing the themes depicted in the tales, avoiding switching from past to present.
6) Regarding the themes explored in the tales, the main ones include marriage, love, corruption, and chivalry.
7) The tales cover various themes, with a particular focus on love and marriage.
8) Canterbury Cathedral symbolizes the celestial city of Jerusalem, highlighting that we are all pilgrims on a journey towards this spiritual destination.