Past Tense

The past is formed using the following:
past participle (in a proper gender form) + present form of the verb být (to be)

!!Note!!: The present form of the verb být is omitted in the 3rd person)

past participle: infinitive (minus ending -t) + suffix (l - li, la - ly, lo - la)

present form of the verb být for the past tense
1. person (singular, plural): jsem - jsme
2. person (singular, plural): jsi - jste
3. person (singular, plural): --

Dělat - to do
masculine
1. person (singular, plural): dělal jsem - dělali jsme
2. person (singular, plural): dělal jsi - dělali jste
3. person (singular, plural): dělal - dělali

feminine
1. person (singular, plural): dělala jsem - dělaly jsme
2. person (singular, plural): dělala jsi - dělaly jste
3. person (singular, plural): dělala - dělaly

neuter
1. person (singular, plural): dělalo jsem - dělaa jsme
2. person (singular, plural): dělalo jsi - dělala jste
3. person (singular, plural): dělalo - dělala

Zpívat - to sing
Já jsem zpíval. (I was singing, masculine)
Já jsem zpívala. (I was singing, feminine)
Já jsem zpívalo. (I was singing, neuter)
Ty jsi zpíval. (You were singing, masculine)
Ty jsi zpívala. (You were singing, feminine)
Ty jsi zpívalo. (You were singing, neuter)
On zpíval. (He was singing.)
Ona zpívala. (She was singing.)
Ono zpívalo. (It was singing.)
My jsme zpívali. (We were singing, masculine, or mixed group)
My jsme zpívaly. (We were singing, feminine)
My jsme zpívala. (We were singing, neuter)
Vy jste zpívali. (You were singing, masculine, or mixed group)
Vy jste zpívaly. (You were singing, feminine)
Vy jste zpívala. (You were singing, neuter)
Oni zpívali. (They were singing, masculine, or mixed group)
Ony zpívaly. (They were singing, feminine)
Ona zpívala. (They were singing, neuter)

Reflexive verbs
Reflexive verbs have "se" or "si" added to the main verb.

povídat si - to talk, to have a talk
mýt se - to wash oneself

The past tense of the reflexive verbs is formed as for the non-reflexive verbs. "Se" and "Se" do not change. They usually stand after the main verb. However, they can often stand before the main verb.

There is no general rule for that, but usually, when the subject is expressed, "se" or "si" moves before the main verb.

On se myl. (He was washing himself.)
Myl se. (He was washing himself.)
Povídali si. (They were talking.)
Oni si povídali. (They were talking.)
Já jsem se myl. (I was washing myself.)
Já se myl. (I was washing myself.)