The diagram reveal the structure is a basic rocket engine and how it works, firstly the engine has two types of vessel, the Fuel container and the Oxygen tank; these are connected through other pieces.
For example, the fuel container is linked with fuel pump and one of the injectors prior to the fuel can pass to the combustion chamber, in the other hand, oxygen tank need to be connected to an oxidizer pump and the other injector to reach the ignition chamber in which eventually, both elements can be mixed to produce combustion products. After that process, this ignition products are released through a nozzle.
For instance, we have knowledge about the gas boiler and it functions, this gas boiler has less the same process in which two various elements (gas and water) are combined to give us hot water. They also have different hoses who drive these elements into a chamber in which they mixed. 
The diagram reveal the structure is a basic rocket engine and how it works,  
firstly
 the engine has two types of vessel, the  
Fuel
 container and the Oxygen tank; these  
are connected
 through other pieces. 
For example
, the  
fuel
 container  
is linked
 with  
fuel
 pump and one of the injectors prior to the  
fuel
 can pass to the combustion chamber, in the other hand, oxygen tank need to  
be connected
 to an oxidizer pump and the other injector to reach the ignition chamber in which  
eventually
, both elements can  
be mixed
 to produce combustion products. After that process, this ignition products  
are released
 through a nozzle. 
For instance
, we have knowledge about the gas boiler and it functions, this gas boiler has less the same process in which two various elements (gas and water)  
are combined
 to give us hot water. They  
also
 have  
different
 hoses who drive these elements into a chamber in which they mixed.