Simulate Ar(1) process with different y0 values and uniform distribution

#1
I need to plot an Ar(1) graph for the process yk = 0.75yk-1 + ek.

for y0=1 and another graph for y0=10.

assume ek is uniformly distributed on interval [-0.5,0.5].

i have the following code but i am not sure how to control y0.

Code:
#----------#Start#---------#
rm(list=ls())
library(tseries)
#library(zoo)
set.seed(0)
y<-arima.sim(model=list(ar=.75), n=100, innov = runif(100, 0, 1))
y.1<-y-0.5
ts.plot(y.1)