oke so here we go
since you said you’re a beginner i’ll try to give some extra information so maybe it’s to much information then just take the flows and go 
if after this you have any questions you can ask!

for now i got 5 flows to show notice that the dim up timed and dim down timed are darker grey this means the flows have been disabled
before we start with the flow you have to create a Variable in the homey app More>Logic>+ sign in upper right corner
type a name i used Test.DimsettingGroup1 but you can pick any name you like if you want multiple groups (for different dimvalues) make a second one with another name
in type select Number
fill in a value of 0 as start value
the first flow i made is a flow that triggers every 5 minutes in this flow we look for the current value of the dimsetting and check what value it is if it is not greater then 0.89 we calculate the same value and do it + 0.1 if it is greater then 0.89 it sets the var to 1 and the flow turns itself off
with these setting every 5 minutes the setting will get 10% brighter (smartlight dimvalues are between 0 and 1 so or example 0.44 is 44%
if you want to max out the light at 80% for example set the value under else to 0.8
and the compare under “and” to 0.69
for making the dimsetting go down we do almost the same except now we check it is not than 0.11 if is not we subtract 0.1
below 0.11 we set the value to 0.01 / 1% and turn the flow off
keep in mind thought that the 1% may cause some problems because not al lights accept 1% and go back to a minimum of 10%
to activate the flows we simply create a extra flow select the moment we want it to start in this flow i used sun sets in 15 minutes and then we turn on the flow dim up timed
from this point every 5minutes the dimsetting goes up by 0.1 until it reaches 1 and then turns off again
logically we do the same when the sun rises
now we go to the flow that activates your lights and instead of giving it a lamp on we give it a dim to and as a value we select the Var. of your dimsetting in this examples i used 4 lights to and gave them 2 different group setting you can do this by just making this whole story twice with 2 different variables
hope this long story helps and that i understood correctly what you want 
if you have any questions feel free to ask!

