R - Group by Date then Sum by unique ID - r

Question

Here is my code - creating a dashboard that will filter by date. One tab will show our wellness survey data, the other will show post-practice loading data. I am pulling in the first 3 columns from "post.csv" which are Date, Name, Daily. Then I am looking to create and add the next 3 columns with the math.
Where I am first stuck is that I need my Daily_Load to aggregate data for a specific athlete on the given Date. Then I need to create a rolling 7-day sum for each athlete using the Daily load data from the last 7 days (including Date selected). A 28-Day Rolling Sum/4 and 7-Day/28-Rolling is the last piece.
Thanks again for all of the help!
library(shiny)
library(dplyr)
library(lubridate)
library(ggplot2)
library(DT)
library(zoo)
library(tidyr)
library(tidyverse)
library(data.table)
library(RcppRoll)
AM_Wellness <- read.csv("amwell.csv", stringsAsFactors = FALSE)
Post_Practice <- read.csv("post.csv", stringsAsFactors = FALSE)
Post_Data <- Post_Practice[, 1:3]
Daily_Load <- aggregate(Daily~ ., Post_Data, sum)
Acute_Load <- rollsum(Post_Data$Daily, 7, fill = NA, align = "right")
Chronic_Load <- rollsum(Post_Data$Daily, 28, fill = NA, align = "right")/4
Post_Data['Day Load'] <- aggregate(Daily~ ., Post_Data, sum)
Post_Data['7-Day Sum'] <- Acute_Load
Post_Data['28-Day Rolling'] <- Chronic_Load
Post_Data['Ratio'] <- Acute_Load/Chronic_Load
ui <- fluidPage(
titlePanel("Dashboard"),
sidebarLayout(
sidebarPanel(
dateInput('date',
label = "Date",
value = Sys.Date()
),
selectInput("athleteInput", "Athlete",
choices = c("All"))
),
mainPanel(tabsetPanel(type = "tabs",
tabPanel("AM Wellness", tableOutput("amwell")),
tabPanel("Post Practice", tableOutput("post"))
)
)
)
)
server <- function(input, output) {
output$amwell <- renderTable({
datefilter <- subset(AM_Wellness, AM_Wellness$Date == input$date)
}, hover = TRUE, bordered = TRUE, spacing = "xs", align = "c")
output$post <- renderTable({
datefilter <- subset(Post_Data, Post_Data$Date == input$date)
}, hover = TRUE, bordered = TRUE, spacing = "xs", align = "c")
}
shinyApp(ui = ui, server = server)