调整图例文本，轴标签和轴单位

Question

如何在以下脚本中更改图例文本的大小，轴的标签以及文本单元的大小（在轴上）。

MYPLOT<-map_df(Totallist,function(x) data.frame(MAE = x), .id = "row") %>% 
  mutate(
    row = as.numeric(row) - 1,
    Size= floor(row / 8+1) %>% as.factor,
    Materials= (row %% 8) %>% as.factor) %>%
  ggplot() +
  geom_boxplot(aes(Size, MAE, fill=Materials), position = "dodge")
MYPLOT+ theme_bw()
levels(MYPLOT$data$Materials) <- c("X1","X2","X3","X4","X5","X6","X7","X8")
MYPLOT

我使用this link和this，但我没有成功

Appericiate！