To specify the condition and its effect we use the “If-then” structure in English
e.g.
If you had gone then I would have gone as well.
Had he eaten well he would have become healthier?
etc.
Gujarati sentence formation has few similarities and a few differences. You can easily relate them with English.

1) For If-then in Gujarati, we use pair જો-તો (jo-to)
2)Form of verb હોવું(hovuM) which is હોત(hot) is used in if & then part.
3) In English we use a special form of verbs like “I had”, “I were”, “He would have” etc. In Gujarati, we use normal forms as if saying
If he ate then he became healthier
If he went then I went as well

But the use of હોત(hot) gives the effect of a special form.
Examples will make it clear

“If you had gone then I would have gone as well” -> If you went then I went as well -> જો તું ગયો હોત તો હું પણ ગયો હોત (jo tuM gayo hot to huM paN gayo hot)

If you had spoken then she would have spoken. -> If you spoke then she spoke
->જો તું બોલ્યો હોત તો એ બોલી હોત (jo tuM bolyo hot to e bolI hot)

If he had said then she would have eaten fruit -> If he said then she ate fruit -> જો એણે કહ્યું હોત તો તેણે ફળ ખાધું હોત (jo eNe kahyuM hot to teNe phaL khAdhuM hot)

“If-Then” structure can be used to predict future also. i.e. to indicate what will be the effect if some action is taken.
e.g.
If you go I will cry.
If he studies he will be happy.

In Gujarati, sentence structure is same as English. But we use future tense in both condition and effect part. And we use pair જો-તો (jo-to)

If you go I will cry -> If you will go then I will cry -> જો તું જઈશ તો હું રડીશ (jo tuM jaIsh to huM raDIsh)

2) If singer sings then dancer will dance. -> If singer will sing then dancer will dance -> જો ગાયક ગાશે તો નર્તક નાચશે (jo gAyak gAshe to nartak nAchashe)

“If-then” statements are also used to give general advice
e.g.
“If someone hurts you, then call the police”,
“If you feel chest pain, then take XYZ medicine” etc.

The first half of this statement is in the present tense and the second half is a command/imperative statement.
In Gujarati, we follow the same sentence structure. Only we omit form of હોવું(hovuM) in the first half.
The second half is prepared with the usual command sentence.

Consider the sentence “If someone hurts you, then call the police”.

call the police -> પોલિસને બોલાવો (polisane bolAvo)
Someone hurts you -> કોઈ તમને ઈજા કરે છે (koI tamane IjA kare Che)

If Someone hurts you then call the police -> જો કોઈ તમને ઈજા કરે તો પોલિસને બોલાવો
(jo koI tamane IjA kare to polisane bolAvo)

See we omitted “છે” from “કરે છે” when using in “If” part

example 2) “If you feel chest pain, then take XYZ medicine”
Take XYZ medicine -> XYZ દવા લો (XYZ davA lo)
You feel chest pain -> છાતીમાં દુખાવો થાય છે (ChAtImAM dukhAvo thAy Che)

“If you feel chest pain, then take XYZ medicine” -> જો છાતીમાં દુખાવો થાય તો XYZ દવા લો (jo ChAtImAM dukhAvo thAy to XYZ davA lo )